1. Field of the Invention
The present invention relates to a stud driver and remover for large diameter studs. In particular, the present invention relates to a stud driver and remover for large diameter studs in which the stud driver and remover has an improved construction over the prior art that enables the inventive stud driver and remover to quickly remove large diameter studs that previously had to be removed by drilling the stud out of the workpiece.
2. Description of Related Art
Stud drivers and removers for small diameter studs are known. For example, Kirkland U.S. Pat. No. 2,069,527 discloses a chuck adapted for stud driving and removing in which three relatively small rolls rotatably grasp the stud. In addition, the assignee of the present application has sold a stud driver and remover under the trademark ROLL-GRIP for small diameter studs, i.e., studs having a diameter between three sixteenths of an inch and three inches. These stud drivers and removers have worked very well for the small diameter studs, but are not readily adaptable simply by increasing their size to accommodate removal or driving of large diameter studs, i.e., studs having a diameter of greater than 3/4 inches, due to the larger stud diameters and increase in torque necessary to remove or drive such large diameter studs.
Large diameter studs are used in many industries, such as chemical plants, electrical generators and nuclear facilities. In these industries, it is often required to remove the studs for periodic inspections and/or maintenance. These industrial sites may have between 100-200 or more studs on site. In the past, there were no tools which readily removed the studs. If a tool was available, the tool would either deform the stud during the removal process, thereby rendering the tool incapable of grasping the stud to complete the removal process; or the tool could not withstand the high torque necessary for large diameter stud removal, thereby resulting in a breakdown of the tool. As a consequence, large diameter studs were often drilled out, which required 2-3 hours per stud.